The new arena mode is really not fun. You have no chance to win against someone who was lucky enough to draft a bunch of 1 str units that do nothing.
The card quality is simply too varied for this mode to be even remotely fair. If you have only a couple 10+ str units in "your" deck (sometimes you offered a choice between 4 good cards), they can easily be game winning for your opponent.
Another issue are leaders. Some leaders are simply worth a lot of points, and you cannot make a bad choice. But, again, some people get to draft Henselt, Bran or Eithne, so they get A HUGE advantage with the leader alone.
Finally, I was offered 10 gold cards in total on my very first run. I have over a dozen runs in classic arena mode and never got more than 9 golds. Again, this is totally RNG when you get to choose from 4 solid golds, and your opponent drafts 2 Ciri Novas, Ithlinne and the Brewess: Ritual (with no bronze deathwish units in the deck).
Bottom line, your number of wins in the new mode is 99% draft based since the difference between hilariously bad, simply bad and good (when you have no other choice) cards is too huge. I really looked forward to it, but the experience turned out to be the most frustrating thing I ever experienced in Gwent.